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Russell Kingb9d36b82005-09-12 22:56:56 +01001/*
2 * Watchdog driver for the mpcore watchdog timer
3 *
4 * (c) Copyright 2004 ARM Limited
5 *
6 * Based on the SoftDog driver:
Alan Cox29fa0582008-10-27 15:17:56 +00007 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +00008 * All Rights Reserved.
Russell Kingb9d36b82005-09-12 22:56:56 +01009 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
16 * warranty for any of this software. This material is provided
17 * "AS-IS" and at no charge.
18 *
19 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
20 *
21 */
22#include <linux/module.h>
23#include <linux/moduleparam.h>
Russell Kingb9d36b82005-09-12 22:56:56 +010024#include <linux/types.h>
25#include <linux/miscdevice.h>
26#include <linux/watchdog.h>
27#include <linux/fs.h>
28#include <linux/reboot.h>
29#include <linux/init.h>
30#include <linux/interrupt.h>
Russell Kingd052d1b2005-10-29 19:07:23 +010031#include <linux/platform_device.h>
Alan Cox83ab1a52008-05-19 14:07:15 +010032#include <linux/uaccess.h>
Russell Kingad4162f2005-09-14 09:56:38 +010033
34#include <asm/hardware/arm_twd.h>
Russell Kingb9d36b82005-09-12 22:56:56 +010035
36struct mpcore_wdt {
37 unsigned long timer_alive;
38 struct device *dev;
39 void __iomem *base;
40 int irq;
41 unsigned int perturb;
42 char expect_close;
43};
44
45static struct platform_device *mpcore_wdt_dev;
Russell Kingb9d36b82005-09-12 22:56:56 +010046extern unsigned int mpcore_timer_rate;
47
48#define TIMER_MARGIN 60
49static int mpcore_margin = TIMER_MARGIN;
50module_param(mpcore_margin, int, 0);
Alan Cox83ab1a52008-05-19 14:07:15 +010051MODULE_PARM_DESC(mpcore_margin,
52 "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
53 __MODULE_STRING(TIMER_MARGIN) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010054
55static int nowayout = WATCHDOG_NOWAYOUT;
56module_param(nowayout, int, 0);
Alan Cox83ab1a52008-05-19 14:07:15 +010057MODULE_PARM_DESC(nowayout,
58 "Watchdog cannot be stopped once started (default="
59 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010060
61#define ONLY_TESTING 0
62static int mpcore_noboot = ONLY_TESTING;
63module_param(mpcore_noboot, int, 0);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +000064MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
65 "set to 1 to ignore reboots, 0 to reboot (default="
66 __MODULE_STRING(ONLY_TESTING) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010067
68/*
69 * This is the interrupt handler. Note that we only use this
70 * in testing mode, so don't actually do a reboot here.
71 */
David Howells7d12e782006-10-05 14:55:46 +010072static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
Russell Kingb9d36b82005-09-12 22:56:56 +010073{
74 struct mpcore_wdt *wdt = arg;
75
76 /* Check it really was our interrupt */
77 if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
Alan Cox83ab1a52008-05-19 14:07:15 +010078 dev_printk(KERN_CRIT, wdt->dev,
79 "Triggered - Reboot ignored.\n");
Russell Kingb9d36b82005-09-12 22:56:56 +010080 /* Clear the interrupt on the watchdog */
81 writel(1, wdt->base + TWD_WDOG_INTSTAT);
Russell Kingb9d36b82005-09-12 22:56:56 +010082 return IRQ_HANDLED;
83 }
Russell Kingb9d36b82005-09-12 22:56:56 +010084 return IRQ_NONE;
85}
86
87/*
88 * mpcore_wdt_keepalive - reload the timer
89 *
90 * Note that the spec says a DIFFERENT value must be written to the reload
91 * register each time. The "perturb" variable deals with this by adding 1
92 * to the count every other time the function is called.
93 */
94static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
95{
96 unsigned int count;
97
98 /* Assume prescale is set to 256 */
99 count = (mpcore_timer_rate / 256) * mpcore_margin;
100
101 /* Reload the counter */
Alan Cox83ab1a52008-05-19 14:07:15 +0100102 spin_lock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100103 writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
Russell Kingb9d36b82005-09-12 22:56:56 +0100104 wdt->perturb = wdt->perturb ? 0 : 1;
Alan Cox83ab1a52008-05-19 14:07:15 +0100105 spin_unlock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100106}
107
108static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
109{
Alan Cox83ab1a52008-05-19 14:07:15 +0100110 spin_lock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100111 writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
112 writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
113 writel(0x0, wdt->base + TWD_WDOG_CONTROL);
Alan Cox83ab1a52008-05-19 14:07:15 +0100114 spin_unlock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100115}
116
117static void mpcore_wdt_start(struct mpcore_wdt *wdt)
118{
119 dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
120
Alan Cox83ab1a52008-05-19 14:07:15 +0100121 spin_lock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100122 /* This loads the count register but does NOT start the count yet */
123 mpcore_wdt_keepalive(wdt);
124
125 if (mpcore_noboot) {
126 /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
127 writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
128 } else {
129 /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
130 writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
131 }
Alan Cox83ab1a52008-05-19 14:07:15 +0100132 spin_unlock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100133}
134
135static int mpcore_wdt_set_heartbeat(int t)
136{
137 if (t < 0x0001 || t > 0xFFFF)
138 return -EINVAL;
139
140 mpcore_margin = t;
141 return 0;
142}
143
144/*
145 * /dev/watchdog handling
146 */
147static int mpcore_wdt_open(struct inode *inode, struct file *file)
148{
Russell King3ae5eae2005-11-09 22:32:44 +0000149 struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100150
151 if (test_and_set_bit(0, &wdt->timer_alive))
152 return -EBUSY;
153
154 if (nowayout)
155 __module_get(THIS_MODULE);
156
157 file->private_data = wdt;
158
159 /*
160 * Activate timer
161 */
162 mpcore_wdt_start(wdt);
163
164 return nonseekable_open(inode, file);
165}
166
167static int mpcore_wdt_release(struct inode *inode, struct file *file)
168{
169 struct mpcore_wdt *wdt = file->private_data;
170
171 /*
172 * Shut off the timer.
173 * Lock it in if it's a module and we set nowayout
174 */
Alan Cox83ab1a52008-05-19 14:07:15 +0100175 if (wdt->expect_close == 42)
Russell Kingb9d36b82005-09-12 22:56:56 +0100176 mpcore_wdt_stop(wdt);
Alan Cox83ab1a52008-05-19 14:07:15 +0100177 else {
178 dev_printk(KERN_CRIT, wdt->dev,
179 "unexpected close, not stopping watchdog!\n");
Russell Kingb9d36b82005-09-12 22:56:56 +0100180 mpcore_wdt_keepalive(wdt);
181 }
182 clear_bit(0, &wdt->timer_alive);
183 wdt->expect_close = 0;
184 return 0;
185}
186
Alan Cox83ab1a52008-05-19 14:07:15 +0100187static ssize_t mpcore_wdt_write(struct file *file, const char *data,
188 size_t len, loff_t *ppos)
Russell Kingb9d36b82005-09-12 22:56:56 +0100189{
190 struct mpcore_wdt *wdt = file->private_data;
191
Russell Kingb9d36b82005-09-12 22:56:56 +0100192 /*
193 * Refresh the timer.
194 */
195 if (len) {
196 if (!nowayout) {
197 size_t i;
198
199 /* In case it was set long ago */
200 wdt->expect_close = 0;
201
202 for (i = 0; i != len; i++) {
203 char c;
204
205 if (get_user(c, data + i))
206 return -EFAULT;
207 if (c == 'V')
208 wdt->expect_close = 42;
209 }
210 }
211 mpcore_wdt_keepalive(wdt);
212 }
213 return len;
214}
215
216static struct watchdog_info ident = {
217 .options = WDIOF_SETTIMEOUT |
218 WDIOF_KEEPALIVEPING |
219 WDIOF_MAGICCLOSE,
220 .identity = "MPcore Watchdog",
221};
222
Alan Cox83ab1a52008-05-19 14:07:15 +0100223static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
224 unsigned long arg)
Russell Kingb9d36b82005-09-12 22:56:56 +0100225{
226 struct mpcore_wdt *wdt = file->private_data;
227 int ret;
228 union {
229 struct watchdog_info ident;
230 int i;
231 } uarg;
232
233 if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200234 return -ENOTTY;
Russell Kingb9d36b82005-09-12 22:56:56 +0100235
236 if (_IOC_DIR(cmd) & _IOC_WRITE) {
237 ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
238 if (ret)
239 return -EFAULT;
240 }
241
242 switch (cmd) {
243 case WDIOC_GETSUPPORT:
244 uarg.ident = ident;
245 ret = 0;
246 break;
247
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000248 case WDIOC_GETSTATUS:
249 case WDIOC_GETBOOTSTATUS:
250 uarg.i = 0;
251 ret = 0;
252 break;
253
Russell Kingb9d36b82005-09-12 22:56:56 +0100254 case WDIOC_SETOPTIONS:
255 ret = -EINVAL;
256 if (uarg.i & WDIOS_DISABLECARD) {
257 mpcore_wdt_stop(wdt);
258 ret = 0;
259 }
260 if (uarg.i & WDIOS_ENABLECARD) {
261 mpcore_wdt_start(wdt);
262 ret = 0;
263 }
264 break;
265
Russell Kingb9d36b82005-09-12 22:56:56 +0100266 case WDIOC_KEEPALIVE:
267 mpcore_wdt_keepalive(wdt);
268 ret = 0;
269 break;
270
271 case WDIOC_SETTIMEOUT:
272 ret = mpcore_wdt_set_heartbeat(uarg.i);
273 if (ret)
274 break;
275
276 mpcore_wdt_keepalive(wdt);
277 /* Fall */
278 case WDIOC_GETTIMEOUT:
279 uarg.i = mpcore_margin;
280 ret = 0;
281 break;
282
283 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200284 return -ENOTTY;
Russell Kingb9d36b82005-09-12 22:56:56 +0100285 }
286
287 if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
288 ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
289 if (ret)
290 ret = -EFAULT;
291 }
292 return ret;
293}
294
295/*
296 * System shutdown handler. Turn off the watchdog if we're
297 * restarting or halting the system.
298 */
Russell King3ae5eae2005-11-09 22:32:44 +0000299static void mpcore_wdt_shutdown(struct platform_device *dev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100300{
Russell King3ae5eae2005-11-09 22:32:44 +0000301 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100302
303 if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
304 mpcore_wdt_stop(wdt);
305}
306
307/*
308 * Kernel Interfaces
309 */
Arjan van de Ven62322d22006-07-03 00:24:21 -0700310static const struct file_operations mpcore_wdt_fops = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100311 .owner = THIS_MODULE,
312 .llseek = no_llseek,
313 .write = mpcore_wdt_write,
Alan Cox83ab1a52008-05-19 14:07:15 +0100314 .unlocked_ioctl = mpcore_wdt_ioctl,
Russell Kingb9d36b82005-09-12 22:56:56 +0100315 .open = mpcore_wdt_open,
316 .release = mpcore_wdt_release,
317};
318
319static struct miscdevice mpcore_wdt_miscdev = {
320 .minor = WATCHDOG_MINOR,
321 .name = "watchdog",
322 .fops = &mpcore_wdt_fops,
323};
324
Russell King3ae5eae2005-11-09 22:32:44 +0000325static int __devinit mpcore_wdt_probe(struct platform_device *dev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100326{
Russell Kingb9d36b82005-09-12 22:56:56 +0100327 struct mpcore_wdt *wdt;
328 struct resource *res;
329 int ret;
330
331 /* We only accept one device, and it must have an id of -1 */
332 if (dev->id != -1)
333 return -ENODEV;
334
335 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
336 if (!res) {
337 ret = -ENODEV;
338 goto err_out;
339 }
340
Yoann Padioleaudd00cc42007-07-19 01:49:03 -0700341 wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
Russell Kingb9d36b82005-09-12 22:56:56 +0100342 if (!wdt) {
343 ret = -ENOMEM;
344 goto err_out;
345 }
Russell Kingb9d36b82005-09-12 22:56:56 +0100346
347 wdt->dev = &dev->dev;
348 wdt->irq = platform_get_irq(dev, 0);
David Vrabel48944732006-01-19 17:56:29 +0000349 if (wdt->irq < 0) {
350 ret = -ENXIO;
351 goto err_free;
352 }
H Hartley Sweetenb782a562009-12-04 12:24:04 -0500353 wdt->base = ioremap(res->start, resource_size(res));
Russell Kingb9d36b82005-09-12 22:56:56 +0100354 if (!wdt->base) {
355 ret = -ENOMEM;
356 goto err_free;
357 }
358
Andrew Victore0b79e02006-12-04 15:56:18 +0200359 mpcore_wdt_miscdev.parent = &dev->dev;
Russell Kingb9d36b82005-09-12 22:56:56 +0100360 ret = misc_register(&mpcore_wdt_miscdev);
361 if (ret) {
Alan Cox83ab1a52008-05-19 14:07:15 +0100362 dev_printk(KERN_ERR, _dev,
363 "cannot register miscdev on minor=%d (err=%d)\n",
364 WATCHDOG_MINOR, ret);
Russell Kingb9d36b82005-09-12 22:56:56 +0100365 goto err_misc;
366 }
367
Alan Cox83ab1a52008-05-19 14:07:15 +0100368 ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED,
369 "mpcore_wdt", wdt);
Russell Kingb9d36b82005-09-12 22:56:56 +0100370 if (ret) {
Alan Cox83ab1a52008-05-19 14:07:15 +0100371 dev_printk(KERN_ERR, _dev,
372 "cannot register IRQ%d for watchdog\n", wdt->irq);
Russell Kingb9d36b82005-09-12 22:56:56 +0100373 goto err_irq;
374 }
375
376 mpcore_wdt_stop(wdt);
Russell King3ae5eae2005-11-09 22:32:44 +0000377 platform_set_drvdata(&dev->dev, wdt);
Russell Kingb9d36b82005-09-12 22:56:56 +0100378 mpcore_wdt_dev = dev;
379
380 return 0;
381
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000382err_irq:
Russell Kingb9d36b82005-09-12 22:56:56 +0100383 misc_deregister(&mpcore_wdt_miscdev);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000384err_misc:
Russell Kingb9d36b82005-09-12 22:56:56 +0100385 iounmap(wdt->base);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000386err_free:
Russell Kingb9d36b82005-09-12 22:56:56 +0100387 kfree(wdt);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000388err_out:
Russell Kingb9d36b82005-09-12 22:56:56 +0100389 return ret;
390}
391
Russell King3ae5eae2005-11-09 22:32:44 +0000392static int __devexit mpcore_wdt_remove(struct platform_device *dev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100393{
Russell King3ae5eae2005-11-09 22:32:44 +0000394 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100395
Russell King3ae5eae2005-11-09 22:32:44 +0000396 platform_set_drvdata(dev, NULL);
Russell Kingb9d36b82005-09-12 22:56:56 +0100397
398 misc_deregister(&mpcore_wdt_miscdev);
399
400 mpcore_wdt_dev = NULL;
401
402 free_irq(wdt->irq, wdt);
403 iounmap(wdt->base);
404 kfree(wdt);
405 return 0;
406}
407
Kay Sieversf37d1932008-04-10 21:29:23 -0700408/* work with hotplug and coldplug */
409MODULE_ALIAS("platform:mpcore_wdt");
410
Russell King3ae5eae2005-11-09 22:32:44 +0000411static struct platform_driver mpcore_wdt_driver = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100412 .probe = mpcore_wdt_probe,
413 .remove = __devexit_p(mpcore_wdt_remove),
414 .shutdown = mpcore_wdt_shutdown,
Russell King3ae5eae2005-11-09 22:32:44 +0000415 .driver = {
416 .owner = THIS_MODULE,
417 .name = "mpcore_wdt",
418 },
Russell Kingb9d36b82005-09-12 22:56:56 +0100419};
420
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000421static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. "
422 "mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
Russell Kingb9d36b82005-09-12 22:56:56 +0100423
424static int __init mpcore_wdt_init(void)
425{
426 /*
427 * Check that the margin value is within it's range;
428 * if not reset to the default
429 */
430 if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
431 mpcore_wdt_set_heartbeat(TIMER_MARGIN);
Alan Cox83ab1a52008-05-19 14:07:15 +0100432 printk(KERN_INFO "mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
Russell Kingb9d36b82005-09-12 22:56:56 +0100433 TIMER_MARGIN);
434 }
435
436 printk(banner, mpcore_noboot, mpcore_margin, nowayout);
437
Russell King3ae5eae2005-11-09 22:32:44 +0000438 return platform_driver_register(&mpcore_wdt_driver);
Russell Kingb9d36b82005-09-12 22:56:56 +0100439}
440
441static void __exit mpcore_wdt_exit(void)
442{
Russell King3ae5eae2005-11-09 22:32:44 +0000443 platform_driver_unregister(&mpcore_wdt_driver);
Russell Kingb9d36b82005-09-12 22:56:56 +0100444}
445
446module_init(mpcore_wdt_init);
447module_exit(mpcore_wdt_exit);
448
449MODULE_AUTHOR("ARM Limited");
450MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
451MODULE_LICENSE("GPL");
452MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);